1. Field of the Invention
The present invention relates generally to extended depth-of-field imaging systems, and particularly relates to such a system that utilizes a single lens element in the imaging optical system.
2. Technical Background
Extended depth-of-field (“EDOF”) imaging systems (also referred to as “extended depth-of-focus” imaging systems) have seen increased use in various applications such as biometrics (e.g., iris recognition), bar-code scanners and closed-circuit television (CCTV) systems.
The optical systems of EDOF imaging systems typically include either more than one lens element or include a non-circularly symmetric “wavefront coding” plate arranged in the entrance pupil to impart a complex wavefront shape.
Since EDOF imaging systems are desirable for use in an increasingly greater number of imaging applications that call for small form factors (e.g., cell phones and other hand-held image-capturing devices), there is a need for EDOF imaging systems that are extremely simple and compact but that can still provide EDOF imaging capability.